Surgical Castration Changes Struggle Behavior and Vocalizations in Male Piglets

Area of Science:

• Animal Behavior
• Veterinary Science
• Pain Research

Background:

• Assessing acute pain in livestock is crucial for animal welfare.
• Behavioral indicators are vital for non-invasive pain evaluation in piglets.
• Castration is a common procedure in piglets, often associated with pain.

Purpose of the Study:

• To evaluate behavioral indicators of acute pain in piglets undergoing surgical castration.
• To compare behavioral responses between castrated and sham-castrated piglets.
• To identify reliable behavioral markers for pain assessment in neonatal piglets.

Main Methods:

• Eighty-eight piglets were randomly assigned to surgical castration or sham-castration groups.
• Behavioral indicators including struggle (curl ups, leg kicks, body flailing) and vocalization (duration, peak frequency) were analyzed.
• Procedures were conducted within 24 hours after birth, with identical surgical steps except for the actual castration.

Main Results:

• Castrated piglets exhibited significantly more leg kicks (28.8 vs. 21.3 kicks/min) and body flailing (51.2% vs. 4.4%) than sham piglets.
• High-frequency vocalizations (≥1,000 Hz) were more frequent (23.6 vs. 18.6 calls/min) and tended to be longer in duration (0.45 vs. 0.27 sec/call) in castrated piglets.
• Statistical analysis confirmed significant differences (P < 0.05) for leg kicks, body flailing, and high-frequency calls.

Conclusions:

• Surgical castration demonstrably increases the frequency and intensity of specific behaviors in piglets.
• Leg kicks, body flailing, and high-frequency vocalizations serve as effective behavioral indicators of acute pain during castration.
• These findings support the use of these behavioral indicators for objective pain assessment in veterinary practice and research.